Primary mold of bottle body with handle and method of manufacturing bottle body with handle

ABSTRACT

A primary molded bottle body 1 is blow molded with a bottomed and tubular lower body blank portion 9 suspended and continuously provided from the bottom of an upper body portion 2. The upper body portion 2 comprises a mouth tube 8 continuously provided through a shoulder portion 7 to the top end of a body wall 3 provided at the back portion thereof with a handle piece 4. Only the lower body blank portion 9 of primary molded bottle body 1 is blow molded by biaxial stretching into a lower body portion 9&#39; to obtain a bottle body 1&#39;, so that a large-sized bottle body with a handle having the substantially equal strength to a biaxially stretched blow-molded bottle can be obtained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a primary molded bottle body with ahandle piece made of synthetic resin, and a method of manufacturing abottle body with a handle piece.

2. Description of Related Art

Among synthetic resin made bottles comprising handle pieces, there areknown bottles that have handle pieces formed in advance and separatelyfrom bodies of bottles and fixed to the bodies thereafter. There arealso known bottles that have handle pieces placed to certain positionsof bodies of bottles when the bodies were formed to final products.

As a molding material of synthetic resin for bottles containing liquid,crystalline synthetic resin such as polyethylene terephthalete resin(PET) is preferable when mechanical strength and sanitation of bottlesare concerned.

To form bottles with PET, it is preferable to use a biaxial stretchmolding means because such means brings out an improved mechanicalstrength characteristic of PET.

Known PET-made bottle bodies having handle pieces include, for example,such bottles as described in Japanese patent provisional publication No.58-99350 and Japanese utility model publication No. 2-39926. Accordingto a bottle body shown in Japanese patent provisional publication No.58-99350, a handle piece is formed individually that comprises anengaging portion, such as a protrusion, and is concave at a certainportion thereof. While the bottle body is formed in its complete shapeby blow molding, the engaging portion of the handle piece engages withthe certain portion of the bottle body as the bottle body expands,stretches and deforms. According to a bottle body shown in the Japaneseutility model publication No. 2-39926, a handle piece is provided inwhich a pair of concaves are formed at both sides of the back portion ofthe bottle body, and a pair of the concaves functions as a handle piece.

However, according to the former prior art in which the separatelyformed handle piece is engaged with the bottle body as the bottle bodyexpands and deforms, the engagement of the handle piece and the bottlebody is not always tight enough. It is desired that the engagementthereof be strengthened. To strengthen the engagement between the handlepiece and the bottle body, there was an idea that the blow pressure forforming the bottle body could be increased. However, as the blowpressure is increased, some problems arise in that the engaging portionof the bottle body with the handle piece cracks and the bottle bodyirregularly deforms due to the high pressure.

When a separately formed handle piece is engaged with a bottle body thatwill be stretched by biaxial blow molding, the biaxial stretch blowmolding becomes an insert molding style. The structure of a mold forforming such a bottle body would be complicated and a molding operationthereof would be difficult.

According to the latter prior art in which the handle piece is providedat the back of the bottle body by forming a pair of concaves thereto,the handle piece can be unitedly formed with the bottle body so that itis easier to form the bottle. However, according to this prior art,there is a problem that the handle piece does not satisfactorilyfunction as a handle piece so that it is uneasy to handle the bottle.

Especially when the bottle body has a volume thereof of 1.5 liter ormore, the handle piece, which is provided by a pair of concaves, canhardly function as a handle piece. It is clear that this type of handlepiece cannot be applied to bigger bottles.

Further, according to regular hollow molding bottles (blow moldingbottles), there is a handle piece forming means that is a part of thebottle body and, while blow molding, is bit off by a pair of piece moldswhich forwardly move from opposite sides in the same direction and makecontact with each other. The bit off portion naturally adheres tightly,forming a handle piece, as the molding resin has an adhesivecharacteristic. However, this process cannot be applied to biaxialstretch blow molding bottles because a property of resin applicable forthe regular stretch blow molding and the biaxial stretch blow moldingdiffer. The resin used for the biaxial stretch blow molding does nothave such an adhesive characteristic in which the bit off portiontightly adheres by its own competence.

SUMMARY OF THE INVENTION

The present invention is created to resolve the problems with the priorart. It is recognized that in synthetic resin made large-sized bottles,strong mechanical strength is required at the lower half portion of abottle body rather than the upper half portion thereof. Therefore, theobject of the present invention is to provide a large-sized syntheticresin made bottle securing a handle piece to the bottle body, a lowerhalf portion thereof being made mechanically stronger as it is molded bybiaxial stretch blow molding.

A primary molded bottle body comprising a handle piece according to thepresent invention comprises an upper body and a lower body blankportion.

The upper body comprises a shoulder portion in the shape of a truncatedcone, a mouth tube unitedly formed at the top of the shoulder and ahandle piece formed like a bridge at the backside of a cylindricallyshaped body wall.

The lower body blank portion, which is made of a thicker wall, isunitedly formed at the bottom of the upper body and comprisessubstantially a half spherical shaped bottom wall.

In the primary molded bottle body comprising a handle, the lower bodyblank portion can be wide spread in the upper direction shaping like atruncated cone having a bottom wall.

In the primary molded bottle comprising a handle piece, it is desiredthat the lower body blank portion gradually increases its wall thicknessas it reaches to the bottom.

A method of manufacturing a bottle body with a handle according to thepresent invention comprises two processes.

The first process forms a primary molded bottle body by a hollowmolding. The primary molded bottle body comprises an upper body, whichis a final product of a bottle comprising a handle piece at the backsidethereof, and a lower body blank portion unitedly formed at the bottom ofthe upper body. The lower body blank portion is made of a thicker walland is shaped like a cylinder having a bottom wall.

The second process forms a lower body by a biaxial stretch blow moldingfrom the lower body blank portion while the upper body is held toprevent deformation thereof. The lower body is shaped like a cylinderhaving a bottom wall and comprises a bottom portion having a legportion.

The function of the present invention will be described hereinafter.

A primary molded bottle body, which will be formed into a bottle body bybiaxial stretch blow molding, comprises an upper body and a lower bodyblank portion. The upper body is made of a body wall comprising a handlepiece at the backside thereof, a shoulder portion and a mouth tube. Theupper body of the primary molded bottle body has been shaped to a finalproduct and only the lower body blank portion is stretched by biaxialstretch blow molding and is formed as a bottle.

The primary molded bottle body is shaped almost like a final product ofa bottle, so that the molding means for such should preferably be hollowmolding (blow molding). By molding the primary molded bottle body by thehollow molding means, a handle piece can easily be formed unitedly atthe backside of a bottle body like blow molded bottles of prior art.

The wall of the lower body blank portion of the primary mold is arrangedthicker than that of the upper body so that the lower body blank portioncan be subsequently stretched, so that the wall of the lower body, aftercompletion of the biaxial stretch blow molding, has enough thickness toprovide sufficient mechanical strength to the final product of thebottle.

By forming the lower body blank portion in a cone shape having a bottomwall and with a diameter that gradually increases in the upperdirection, the upper portion of the lower body blank portion can belargely stretched during the biaxial stretch blow molding, so that wholeportions of the lower body blank portion can be stretched sufficiently.

The lower body blank portion of the primary molded bottle body isarranged such that the wall thereof becomes gradually thicker as it goesin the lower direction, so that while the lower body blank portion isbiaxially stretched, the upper portion of the lower body blank portion,which is the hardest portion to stretch among the lower body blankportion, can be stretched sufficiently. Further, since the wall of thebottom portion of the lower body blank portion is arranged sufficientlythick, and is the most stretched part of the lower body blank portion,no portions of the bottom wall, which is largely stretched and forms aleg of the final product of the bottle, will become too thin aftercompletion of the biaxial stretch blow molding.

The final product of the bottle according to the present invention isformed such that only the lower body is sufficiently stretched in bothlateral and longitudinal directions by the biaxial stretch blow moldingand the upper body is stretched only in the lateral direction by aregular hollow (blow) molding. Since the upper body of the bottle ismuch less stretched than the lower body, the mechanical strength of theupper body is weaker than that of the lower body.

However, for a bottle containing liquid, concerning how the liquid issituated in the bottle and how the bottle is handled, the lower body isrequired to have higher mechanical strength. In many cases, the upperbody is required to have less mechanical strength and is only requiredto have enough strength to maintain its shape. Therefore, although theupper body is formed simply by the hollow molding, it naturallypossesses enough strength required for the upper body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side elevational view, a lower body blank portion thereofbeing vertically sectioned, of a preferred embodiment of a primarymolded bottle body according to the present invention;

FIG. 2 shows a vertical sectional view of an upper body of the primarymolded bottle body according to the present invention being fastened tomolds;

FIG. 3 shows a transverse sectional view of the primary molded bottlebody shown in FIG. 2;

FIG. 4 shows a vertical sectional view of the primary molded bottle bodyto be fastened to a blow mold and a bottom mold for biaxial stretch blowmolding;

FIG. 5 shows the primary molded bottle body shown in FIG. 4 beingfastened to the blow mold and the bottom mold; and

FIG. 6 shows a preferred embodiment of a bottle formed by the biaxialstretch blow molding from the primary molded bottle body shown in FIG.1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A preferred embodiment according to the present invention will bedescribed hereinafter referring to the drawings.

FIG. 1 shows a side elevational view of a primary molded bottle body 1with a vertically sectional view of the lower body blank portion thereofaccording to the present invention. This primary molded bottle body 1 asa whole is unitedly formed by a hollow (blow) molding. The primarymolded bottle body 1 comprises an upper body 2 and a lower body blankportion 9 that is unitedly positioned under the upper body 2. The upperbody 2 comprises: a handle piece 4 at the backside thereof that isunitedly bridged to the body 1 in the vertical direction; a body wall 3cylindrically shaped and decreasing its diameter in the upper direction;a shoulder portion 7 positioned on the body wall 3 having a truncatedcone shape formed by a largely sloped taper wall; and a mouth tube 8 ofa short cylindrical shape vertically standing on the shoulder 7. Thelower body blank portion 9 comprises a half spherical shaped bottomportion, arranged such that the thickness of the wall thereof graduallyincreases toward the bottom.

As described above, the primary molded bottle body 1 is a hollow (blow)product, so that it is easy to unitedly form the handle piece 4 at thebackside of the body wall 3 as is easily done in the prior art.

The body wall 3 of the upper body 2 comprises four reinforcement concavewalls 5 vertically caved and placed parallel with each other at a frontside thereof to reinforce the mechanical strength of the body wall 3against outside pressure. In between the body wall 3 portion (rightabove the handle piece 4) and the shoulder portion 7, a finger concave 6is formed for positioning a thumb to make easy control of the bottlebody 1' when the handle piece 4 is handled by a user's hand.

FIGS. 2-5 show an example of a process of biaxial stretch blow moldingto form a bottle body 1' from the primary molded bottle body 1 shown inFIG. 1. According to this process, a mouth holding mold 14, comprisingan extend pin 15 capable of sliding in upper and lower directions, ispositioned to a part located between the mouth tube 8 and the shoulderportion 7 of the primary molded bottle body 1. A pair of upper bodyholding molds 16, a split die, are positioned all around the upper body2 of the primary molded bottle body 1. The mouth holding mold 14 and thepair of upper body holding molds 16 are secured to the upper body 2 ofthe primary mold 1 in such a manner that they prevent the upper body 2from being stretched by an inner pressure caused by the biaxial stretchblow molding.

The heating time of the primary molded bottle body 1 at a temperaturesuitable for the biaxial stretch blow molding is not limited to acertain time. However, when the mouth holding mold 14 and the upper bodyholding molds are secured to the primary molded bottle body 1, the lowerbody blank portion 9 thereof is exposed to air, so that it isadvantageous to use such a condition and heat only the lower body blankportion 9 to the temperature suitable for the biaxial stretch blowmolding.

After the lower body blank portion 9 of the primary molded bottle body 1is heated to the suitable temperature for the biaxial stretch blowmolding, a combination article of a pair of blow molds 17 (a split die)and a bottom mold 20 are secured to a combination article of the primarymolded bottle body 1, the mouth holding mold 14 and the upper bodyholding mold 16, clamping the primary molded bottle body 1 (see FIGS. 4and 5).

The blow mold 17 comprises a clamping mold 18 that is firmly secured tothe upper body holding mold 16 fixed to the primary molded bottle body1, a forming surface 19 that forms a lower body 9' from the lower bodyblank portion 9 along its surface shape, and a bottom mold 20 projectedto a substantially spherical shape. An upper surface of bottom mold 20forms a part of forming surface 19.

FIG. 6 shows a side elevational view of an example of a bottle body 1'formed from the primary molded bottle body shown in FIG. 1 by thebiaxial stretch blow molding. The lower body 9' of the bottle body 1',which is formed by biaxially stretching the lower body blank portion 9,includes a cylindrical wall 10, which comprises four supporting concaves11 therearound each of which is rather narrow and shaped like a ditchand positioned at regular intervals, and a bottom portion 12 unitedlyformed at the bottom of the cylindrical wall 10. The bottom portion 12comprises a leg portion 13 at an edge portion and inner portion ofbottom portion 12 and a spherically caved inside thereof.

The supporting concaves 11 formed around the cylindrical wall 10 aresuch that they improve the mechanical strength of the lower body 9',which receives outer pressure.

The bottle body 1' shown in FIG. 6 is such that the lower body 9' isformed by the biaxial stretch blow molding. Compared with a bottle bodyformed by a regular hollow (blow) molding, the mechanical strength andespecially shock resistance of the bottom portion 12 including the legportion 13 is strengthened. Therefore, even when an user accidentallydrops the bottle 1' containing liquid therein while handling, the bottomportion 12 including the leg portion 13 could resist against such shockand would not collapse at all.

The lower body 9' of the primary molded bottle body 1 is formed by thebiaxial stretch blow molding from the lower body blank portion 9individually without affecting the shape of the upper body 2, so thatany combined shape of the upper body 2 and the lower body 9' can befreely made. For example, the upper body 2 can be formed in a regularcylindrical shape and the lower body 9' in a polygonal cylindricalshape. Therefore, many unique designs can be applied to the bottle body1'.

According to the present invention, the upper body of the bottle body isformed by a regular hollow (blow) molding, so that a handle piece can beeasily formed to the upper body, and that a large sized bottle bodycomprising the handle piece formed by biaxial stretch blow molding canbe easily made.

Higher mechanical strength is required to the lower body of a bottlebody containing liquid therein. The lower body of the bottle bodyaccording to the present invention is formed by biaxial stretch blowmolding, so that sufficient mechanical strength is provided. The upperbody of the bottle body is formed by a regular hollow (blow) molding,but as only a little mechanical strength capable of keeping its ownshape is required to the upper body, the bottle body is furnished withsufficient function as a bottle body for a liquid container.

The method of manufacturing the primary molded bottle body is a regularhollow molding, and the forming means for the lower body of the bottlebody is a regular biaxial stretch blow molding, so that it is easy toform bottles.

The lower body of the primary molded bottle body is formed by thebiaxial stretch blow molding from the lower body blank portionindividually without affecting the shape of the upper body, so that anycombined shape of the upper body and the lower body can be freely made.Therefore, many unique designs can be applied to the bottle bodies,which could improve commercial value of the bottle.

We claim:
 1. A bottle body with a handle formed in a primary mold, thebottle body comprising:a final upper body having a first wall thicknessformed by a first blow molding operation, the final upper bodycomprising a shoulder portion in the shape of a truncated cone, a mouthtube integrally formed at a top of said shoulder portion, and a handlepiece formed to bridge a backside of a cylindrical body wall; and alower intermediate body blank portion formed by the first blow moldingoperation, said lower intermediate body blank portion being integrallyformed at a bottom of said upper body and having a second wall thicknessgreater than said first wall thickness such that said lower intermediatebody blank portion is suitable for subsequent additional blowingcomprising biaxial stretch blow molding in a second blow operation toform a final configuration that is further stretched, said intermediatelower body blank portion having a bottom wall with a substantiallyhemi-spherical shape and diverging walls spreading outwardly toward saidupper body and being shaped like a downwardly descending truncated conehaving the hemi-spherical bottom wall at a point of truncation.
 2. Theprimary molded bottle body with handle as claimed in claim 1, whereinsaid lower body blank portion gradually increases in wall thicknesstoward said bottom wall.
 3. A method of manufacturing a molded bottlebody with a blown integral handle, comprising:holding a primary moldedbottle body in a first mold, said primary molded bottle body comprisingan upper body that is a final product with an integral blown handlepiece formed at a backside thereof during hollow molding, and a lowerintermediate body blank portion integrally formed at a bottom of saidupper body, said lower intermediate body blank portion having a thickerwall thickness than said upper body and being shaped like a cylinderwith a bottom wall; and forming a final lower body by biaxial stretchblow molding said lower intermediate body blank portion while holdingsaid upper body to prevent deformation thereof, said final lower bodybeing shaped like a cylinder with a bottom wall and having a bottomportion with an annular leg portion at a bottom thereof.
 4. The methodof claim 3, wherein said step of holding the primary molded bottle bodycomprises holding said upper body by retention of said upper body in thefirst mold and the step of forming a final lower body is performed in asecond larger mold that encompasses the first mold.
 5. A bottle bodywith an integral blown handle having an upper body with the handleformed and a lower body formed by the following process steps:holding aprimary molded bottle body in a first mold, said primary molded bottlebody comprising an upper body having a first wall thickness, said upperbody being a final product with an integral blown handle piece formed ata backside thereof during hollow molding, and a lower intermediate bodyblank portion integrally formed at a bottom of said upper body, saidlower intermediate body blank portion having a second wall thicknessthicker than said first wall thickness, said lower intermediate bodyblank portion being shaped like a truncated cone with a bottom wall; andforming a final lower body by biaxial stretch blow molding said lowerintermediate body blank portion while holding said upper body to preventdeformation thereof, said final lower body being shaped like a cylinderwith a bottom wall and having a bottom portion with an annular legportion at a bottom thereof.